I am using CPLEX 12.3 on Windows XP to solve the attached LP. When I use the callable library, the optimal value is 0.162602, but the value returned by Interactive CPLEX is 1.0000, which is the right solution.
Is there any explanation to such a situation?

I think you should provide the code of Build_LP and some details about inst_ID and obj_value. Also, you should make clear how you created the .lp file. Furthermore, it might be usefull to create a sav-file instead of an lp-file.

Re: CPLEX callable library returning strange optimal solutions

I think you should provide the code of Build_LP and some details about inst_ID and obj_value. Also, you should make clear how you created the .lp file. Furthermore, it might be usefull to create a sav-file instead of an lp-file.